1. Field of the Invention
The present invention relates to a data recording medium, a recording apparatus and to a recording method for recording information to this data recording medium.
2. Description of Related Art
Data recording devices for optically recording information, and particularly digital data, to a storage medium are commonly used as a convenient means of mass data storage.
Phase change optical discs are one type of optical data recording medium. To record to a phase change optical disc a semiconductor laser emits an optical beam to a spinning disc to heat and melt a recording film on the disc. The achieved temperature and the cooling process (rate) of the molten film can be regulated by controlling the power of the laser beam, thereby inducing a phase change in the recording film.
When laser power is high, the recording film cools rapidly from a high temperature state and thus becomes amorphous. When a relatively low power laser beam is emitted, the recording film cools gradually from a medium high temperature state, and thus crystallizes. The resulting amorphous parts of the recording film are commonly known as xe2x80x9cmarks,xe2x80x9d and the crystallized part between any two marks is known as a xe2x80x9cspace.xe2x80x9d Two-value binary information can thus be recorded using these marks and spaces. When a laser beam is emitted at a high power setting to form a mark, the laser is referred to as operating at xe2x80x9cpeak power.xe2x80x9d When the laser is emitted at low power to form a space, the laser is said to operate at a xe2x80x9cbias powerxe2x80x9d level.
During data reproduction, a laser beam is emitted at a power level low enough to not induce a phase change, and its reflection is then detected. Reflectivity from an amorphous mark is normally low, and is high from a crystalline space. A read signal can therefore be generated by detecting the difference in light reflected from the marks and spaces.
Data can also be recorded to a phase change disc using a mark position recording method (also known as PPM) or a mark edge recording method (also known as PWM). Mark edge recording normally achieves a higher recording density.
Mark edge recording typically records longer marks than recorded by the mark position recording method. When a laser emits at peak power to a phase change disc, heat accumulation in the recording film results in the mark width increasing radially to the disc towards the end part of the mark. In a direct overwrite recording method this can result in part of a mark not being overwritten or completely erased, resulting in a significant loss of signal quality due to signal crosstalk between tracks during reproduction.
Recording density can also be increased by shortening the lengths of the recorded marks and spaces, Thermal interference can occur when the spaces, in particular, are shortened beyond a certain point. This thermal interference can result in heat at the trailing edge of a recorded mark travelling through the following space, thus affecting heat distribution at the beginning of the next mark. Heat at the beginning of one recorded mark can also travel back through the preceding space and adversely affect the cooling process of the preceding mark. When such thermal interference occurs with conventional recording methods, the positions of the leading and trailing edges can shift, thus increasing the error rate during data reproduction.
Addressing this problem, Japanese Unexamined Patent Application Publication (kokai) H07-129959 (U.S. Pat. Nos. 5,490,126 and 5,636,194) teaches a recording method whereby a signal for forming a mark in mark edge recording is analyzed into three parts, a constant width beginning part, a middle part having pulses with a constant period, and a constant width end part, and this signal is then used to drive recording by rapidly switching the output of a two-value laser beam during mark formation.
With this method, the width of the middle part of a long mark is substantially constant and does not spread because laser output is driven with a constant period pulse current producing the minimum power required for mark formation. Jitter at the leading and trailing edges of the mark also does not increase during direct overwrite recording because a constant width laser beam is emitted to the leading and trailing end parts of the mark.
It is also possible to detect whether a mark or spaces before and after a mark is long or short, and change the position at which the leading and trailing parts of a mark are recorded according to the length of the mark and the leading and trailing spaces. This makes it possible to compensate during recording for peak shifts caused by thermal interference.
Japanese Patent Application 5-279513 does not, however, teach a method for determining the optimum positions of the leading and trailing parts of a mark.
If the method of optimizing the leading and trailing edge positions is not defined, the reliability of the optimized recording will be low. Furthermore, even if optimized recording is achieved, it will be at the expense of excessive time spent searching for the optimum position and excessive circuit cost.
A method for changing the leading and trailing edge positions of a mark based on the data being recorded has also been invented as a means of achieving high density data recording. A problem with this method, however, is that the edge of a recorded mark can move due to thermal interference as described above. Such edge movement is also highly dependent upon the disc format and the makeup of the recording film, and if either of these change even slightly, optimized recording cannot be achieved.
With consideration for the above described problems, an object of the present invention is to provide a method and apparatus for easily determining the optimum positions the leading and trailing edges of each mark, thereby achieving optimized recording, even when the disc format, recording film composition, and recording apparatus characteristics vary.
To achieve these objects, according to the first aspect of the invention, a data recording medium having a plurality of concentric or spiral tracks for recording information represented as marks and spaces between the marks, the marks being formed by emitting to a track recording surface an optical beam modulated by a plurality of drive pulses where the drive pulse count is adjusted according to a length of a mark part in the original signal to be recorded to the track, said data recording medium comprises:
a data recording area for recording data, and
a specific information recording area for recording when the data recording medium is loaded into a particular recording device
device-specific information specific to the particular recording device, and
at least one of a specific first pulse position Tu and a specific last pulse position Td of a drive pulse sequence required by the particular recording device to record said marks to the data recording medium.
According to the second aspect of the invention, in the data recording medium as set forth in the first aspect, the device-specific information includes at least one of the following: a name of the particular recording device manufacturer, a product number, a location where the particular recording device was produced, and a production date.
According to the third aspect of the invention, in the data recording medium as set forth in the first aspect, the specific information recording area further records temporary power information indicative of a power level of an optical beam used for determining at least one of a specific first pulse position Tu and a specific last pulse position Td,
said temporary power information including at least one of the following: a peak power setting, bias power setting, margin constant, and asymmetry.
According to the fourth aspect of the invention, in the data recording medium as set forth in the second aspect, the specific information recording area further records a pattern signal for determining said temporary power information.
According to the fifth aspect of the invention, in the data recording medium as set forth in the first aspect, the specific information recording area further records operational power information indicative of a power level of an optical beam used for actual data recording in the data recording area,
said operational power information including at least one of the following: a peak power setting, bias power setting, and margin constant.
According to the sixth aspect of the invention, in the data recording medium as set forth in the fifth aspect, the specific information recording area further records a pattern signal for determining said operational power information.
According to the seventh aspect of the invention, in the data recording medium as set forth in the first aspect, said specific information recording area further records an asymmetry information used for determining at least one of a specific first pulse position Tu and a specific last pulse position Td.
According to the eighth aspect of the invention, in the data recording medium as set forth in the first aspect, further comprises:
a control information recording area for prerecording at least one of a typical first drive pulse position Tu and a typical last drive pulse position Td of a drive pulse sequence required for recording said marks to the data recording medium.
According to the ninth aspect of the invention, in the data recording medium as set forth in the first aspect, said specific information recording area is provided for recording at least one of a specific first pulse position Tu and a specific last pulse position Td, and a device-specific information as a data set, said data set being recorded for a plurality of different recording devices.
According to the tenth aspect of the invention, in the recording and reproducing device for recording information to and reproducing information from a data recording medium,
said data recording medium having a plurality of concentric or spiral tracks for recording information represented as marks and spaces between the marks, the marks being formed by emitting to a track recording surface an optical beam modulated by a plurality of drive pulses where the drive pulse count is adjusted according to a length of a mark part in the original signal to be recorded to the track,
a data recording area for recording data, and
a specific information recording area for recording when the data recording medium is loaded into a particular recording device
device-specific information specific to the particular recording device, and
at least one of a specific first pulse position Tu and a specific last pulse position Td of a drive pulse sequence required by the particular recording device to record said marks to the data recording medium,
the recording and reproducing device comprises:
a reading means for reading device-specific information specific to the data recording medium from a particular area of the data recording medium; and
memory for storing said read medium-specific information.
According to the eleventh aspect of the invention, in the recording and reproducing device as set forth in the tenth aspect, the medium-specific information includes at least one of the following: a name of the data recording medium manufacturer, a product number, a location where the data recording medium was produced, and a production date.
According to the twelfth aspect of the invention, in the recording and reproducing device as set forth in the tenth aspect, the memory further stores temporary power information indicative of a power level of an optical beam used for determining a specific first pulse position Tu and/or specific last pulse position Td,
said temporary power information including at least one of the following: a peak power setting, bias power setting, margin constant, and asymmetry.
According to the thirteenth aspect of the invention, in the recording and reproducing device as set forth in the twelfth aspect, the memory further stores a pattern signal for determining said temporary power information.
According to the 14th aspect of the invention, in the recording and reproducing device as set forth in the tenth aspect, the memory further stores operational power information indicative of a power level of an optical beam used for actual data recording in the data recording area,
said operational power information including at least one of the following: a peak power setting, bias power setting, and margin constant.
According to the 15th aspect of the invention, in the recording and reproducing device as set forth in the 14th aspect, the memory further stores a pattern signal for determining said operational power information.
According to the 16th aspect of the invention, in the recording and reproducing device as set forth in the tenth aspect, said memory further records an asymmetry information used for determining at least one of a specific first pulse position Tu and a specific last pulse position Td.
According to the 17th aspect of the invention, in the recording and reproducing device as set forth in the tenth aspect, the memory further stores said specific first pulse position Tu and/or said specific last pulse position Td.
According to the 18th aspect of the invention, in the recording and reproducing device as set forth in the tenth aspect, the memory further stores medium-specific information for a plurality of different data recording media used in the recording and reproducing device.
According to the 19th aspect of the invention, in a recording method for recording to a data recording medium, said data recording medium having a plurality of concentric or spiral tracks for recording information represented as marks and spaces between the marks, the marks being formed by emitting to a track recording surface an optical beam modulated by a plurality of drive pulses where the drive pulse count is adjusted according to a length of a mark part in the original signal to be recorded to the track,
a data recording area for recording data, and
a specific information recording area for recording when the data recording medium is loaded into a particular recording device
device-specific information specific to the particular recording device, and
at least one of a specific first pulse position Tu and a specific last pulse position Td of a drive pulse sequence required by the particular recording device to record said marks to the data recording medium,
the recording method comprises steps for:
determining said specific first pulse position Tu and/or said specific last pulse position Td; and
then recording data to the data recording area.
According to the 20th aspect of the invention, in the recording method as set forth in the 19th aspect, the specific first pulse position Tu is obtained from a length of a mark part and immediately preceding space part in a pattern signal, and
the specific last pulse position Td is obtained from a length of a mark part and immediately following space part in a pattern signal.
According to the 21st aspect of the invention, in the recording method as set forth in the 19th aspect, the specific first pulse position Tu is expressed as a time difference TF between a first reference point R1, which is a leading edge of a mark part in the pattern signal to be recorded, and a first edge of the first pulse in a plurality of drive pulses, and
specific last pulse position Td is expressed as a time difference TL between a second reference point R2, which has a specific known position relative to a trailing edge of a mark part in the pattern signal to be recorded, and a trailing edge of the last pulse in a plurality of drive pulses.
According to the 22nd aspect of the invention, in the recording method as set forth in the 20th aspect, the pattern signal contains an adjustment signal for obtaining a DSV of 0.
According to the 23rd aspect of the invention, in the recording method as set forth in the 19th aspect, the specific first pulse position Tu and/or specific last pulse position Td is determined by reproducing a specific information recording area of the data recording medium to obtain necessary information.
According to the 24th aspect of the invention, in the recording method as set forth in the 19th aspect, the specific first pulse position Tu and/or specific last pulse position Td is determined by reading information from memory in a particular recording and reproducing device in which the data recording medium is used to obtain necessary information.
According to the 25th aspect of the invention, in the recording method as set forth in the 19th aspect, the information determined for the specific first pulse position Tu and/or specific last pulse position Td is recorded to the specific information recording area of the data recording medium in conjunction with device-specific information specific to the particular recording and reproducing device.
According to the 26th aspect of the invention, in the recording method as set forth in the 19th aspect, the information determined for the specific first pulse position Tu and/or specific last pulse position Td is recorded in memory in a particular recording and reproducing device in conjunction with device-specific information specific to the particular recording and reproducing device.
According to the 27th aspect of the invention, in the recording method as set forth in the 19th aspect, temporary power information indicative of a power level of an optical beam used for determining a specific first pulse position Tu and/or specific last pulse position Td is further recorded to the specific information recording area of the data recording medium,
said temporary power information including at least one of the following: a peak power setting, bias power setting, margin constant, and asymmetry.
According to the 28th aspect of the invention, in the recording method as set forth in the 27th aspect, a pattern signal for determining said temporary power information is further recorded to said specific information recording area.
According to the 29th aspect of the invention, in the recording method as set forth in the 19th aspect, operational power information indicative of a power level of an optical beam used for actual data recording in the data recording area is further recorded to the specific information recording area of the data recording medium,
said operational power information including at least one of the following: a peak power setting, bias power setting, and margin constant.
According to the 30th aspect of the invention, in the recording method as set forth in the 29th aspect, a pattern signal for determining said operational power information is further recorded to said specific information recording area.
According to the 31st aspect of the invention, in the recording method as set forth in the 19th aspect, said specific information recording area further records an asymmetry information used for determining at least one of a specific first pulse position Tu and a specific last pulse position Td.
According to the 32nd aspect of the invention, in the recording method for recording to a data recording medium, said data recording medium having a plurality of concentric or spiral tracks for recording information represented as marks and spaces between the marks, the marks being formed by emitting to a track recording surface an optical beam modulated by a plurality of drive pulses where the drive pulse count is adjusted according to a length of a mark part in the original signal to be recorded to the track,
a data recording area for recording data, and
a specific information recording area for recording when the data recording medium is loaded into a particular recording device
device-specific information specific to the particular recording device, and
at least one of a specific first pulse position Tu and a specific last pulse position Td of a drive pulse sequence required by the particular recording device to record said marks to the data recording medium,
the recording method comprises steps for:
determining emission power of an optical beam for recording said marks; and
then determining a specific first pulse position Tu and/or specific last pulse position Td.
According to the 33rd aspect of the invention, in the recording method as set forth in the 32nd aspect, the optical beam emission power is determined by recording a predetermined specified pattern signal to the data recording medium.
According to the 34th aspect of the invention, in the recording method as set forth in the 33rd aspect, the specified pattern signal contains a single signal.
According to the 35th aspect of the invention, in the recording method as set forth in the 33rd aspect, the specified pattern signal contains an adjustment signal for obtaining a DSV of 0.
According to the 36th aspect of the invention, in the recording method as set forth in the 33rd aspect, the specific pattern signal recorded to the data recording medium is reproduced, the reproduced specific pattern signal is compared with a specific pattern signal for recording, and the emission power is set so that a difference between the compared signals is a specific value or less.
According to the 37th aspect of the invention, in the recording method as set forth in the 33rd aspect, the predetermined specific pattern signal is prerecorded to the data recording medium.
According to the 38th aspect of the invention, in the recording method as set forth in the 33rd aspect, the predetermined specific pattern signal is prerecorded in the recording device.
According to the 39th aspect of the invention, in the recording method as set forth in the 33rd aspect, the emission power determined for a specific data recording medium is recorded to said specific data recording medium.
According to the 40th aspect of the invention, in the recording method as set forth in the 33rd aspect, the emission power determined for a specific data recording medium is stored in the recording device in conjunction with the medium-specific information for said specific data recording medium.
According to the 41st aspect of the invention, in the recording method as set forth in the 32nd aspect, temporary power information indicative of a power level of an optical beam used for determining a specific first pulse position Tu and/or specific last pulse position Td is further recorded to the specific information recording area of the data recording medium,
said temporary power information including at least one of the following: a peak power setting, bias power setting, margin constant, and asymmetry.
According to the 42nd aspect of the invention, in the recording method as set forth in the 41st aspect, wherein a pattern signal for determining said temporary power information is further recorded to said specific information recording area.
According to the 43rd aspect of the invention, in the recording method as set forth in the 32nd aspect, operational power information indicative of a power level of an optical beam used for actual data recording in the data recording area is further recorded to the specific information recording area of the data recording medium,
said operational power information including at least one of the following: a peak power setting, bias power setting, and margin constant.
According to the 44th aspect of the invention, in the recording method as set forth in the 43rd aspect, a pattern signal for determining said operational power information is further recorded to said specific information recording area.
According to the 45th aspect of the invention, in a recording method for recording to a data recording medium, said data recording medium having a plurality of concentric or spiral tracks for recording information represented as marks and spaces between the marks, the marks being formed by emitting to a track recording surface an optical beam modulated by a plurality of drive pulses where the drive pulse count is adjusted according to a length of a mark part in the original signal to be recorded to the track,
a data recording area for recording data, and
a specific information recording area for recording when the data recording medium is loaded into a particular recording device
device-specific information specific to the particular recording device, and
at least one of a specific first pulse position Tu and a specific last pulse position Td of a drive pulse sequence required by the particular recording device to record said marks to the data recording medium,
the recording method comprises steps for:
determining a specific first pulse position Tu and/or specific last pulse position Td, and
then determining emission power of an optical beam for recording said marks.
According to the 46th aspect of the invention, in the recording method as set forth in the 45th aspect, the optical beam emission power is determined by recording a predetermined specified pattern signal to the data recording medium.
According to the 47th aspect of the invention, in the recording method as set forth in the 46th aspect, the predetermined specific pattern signal is prerecorded to the data recording medium.
According to the 48th aspect of the invention, in the recording method as set forth in the 46th aspect, the predetermined specific pattern signal is prerecorded in the recording device.
According to the 49th aspect of the invention, in the recording method as set forth in the 46th aspect, the emission power determined for a specific data recording medium is recorded to said specific data recording medium.
According to the 50th aspect of the invention, in the recording method as set forth in the 46th aspect, the emission power determined for a specific data recording medium is stored in the recording device in conjunction with the medium-specific information for said specific data recording medium.
According to the 51st aspect of the invention, in the recording method as set forth in the 45th aspect, temporary power information indicative of a power level of an optical beam used for determining a specific first pulse position Tu and/or specific last pulse position Td is further recorded to the specific information recording area of the data recording medium,
said temporary power information including at least one of the following: a peak power setting, bias power setting, margin constant, and asymmetry.
According to the 52nd aspect of the invention, in the recording method as set forth in the 51st aspect, a pattern signal for determining said temporary power information is further recorded to said specific information recording area.
According to the 53rd aspect of the invention, in the recording method as set forth in the 45th aspect, operational power information indicative of a power level of an optical beam used for actual data recording in the data recording area is further recorded to the specific information recording area of the data recording medium,
said operational power information including at least one of the following: a peak power setting, bias power setting, and margin constant.
According to the 54th aspect of the invention, in the recording method as set forth in the 53rd aspect, a pattern signal for determining said operational power information is further recorded to said specific information recording area.
According to the 55th aspect of the invention, in the recording method as set forth in the 45th aspect, said specific information recording area further records an asymmetry information used for determining at least one of a specific first pulse position Tu and a specific last pulse position Td.
According to the 56th aspect of the invention, in a recording method for recording to a data recording medium, said data recording medium having a plurality of concentric or spiral tracks for recording information represented as marks and spaces between the marks, the marks being formed by emitting to a track recording surface an optical beam modulated by a plurality of drive pulses where the drive pulse count is adjusted according to a length of a mark part in the original signal to be recorded to the track,
a data recording area for recording data, and
a specific information recording area for recording when the data recording medium is loaded into a particular recording device
device-specific information specific to the particular recording device, and in conjunction therewith
at least one of a specific first pulse position Tu and a specific last pulse position Td of a drive pulse sequence required by the particular recording device to record said marks to the data recording medium,
the recording method comprises steps for:
compensating for group delay so that a same group delay level is obtained in a read signal even when the frequency of the recorded signal differs; and
then determining a specific first pulse position Tu and/or specific last pulse position Td.
According to the 57th aspect of the invention, in the recording method as set forth in the 56th aspect, wherein group delay compensation is accomplished by recording a test signal having a space signal component of a specific length to the data recording medium.
According to the 58th aspect of the invention, in the recording method as set forth in the 57th aspect, wherein the test signal is an embossed signal prerecorded to the data recording medium.
According to the 59th aspect of the invention, in the recording method as set forth in the 57th aspect, the test signal is prerecorded to a specific area of the data recording medium.
According to the 60th aspect of the invention, in the recording method as set forth in the 57th aspect, the test signal is prerecorded to the recording device.
According to the 61st aspect of the invention, in the recording method as set forth in the 57th aspect, group delay compensation is performed to minimize jitter in the reproduced test signal.
According to the 62nd aspect of the invention, in the recording method as set forth in the 56th aspect, temporary power information indicative of a power level of an optical beam used for determining a specific first pulse position Tu and/or specific last pulse position Td is further recorded to the specific information recording area of the data recording medium,
said temporary power information including at least one of the following: a peak power setting, bias power setting, margin constant, and asymmetry.
According to the 63rd aspect of the invention, in the recording method as set forth in the 62nd aspect, a pattern signal for determining said temporary power information is further recorded to said specific information recording area.
According to the 64th aspect of the invention, in the recording method as set forth in the 56th aspect, operational power information indicative of a power level of an optical beam used for actual data recording in the data recording area is further recorded to the specific information recording area of the data recording medium,
said operational power information including at least one of the following: a peak power setting, bias power setting, and margin constant.
According to the 65th aspect of the invention, in the recording method as set forth in the 64th aspect, a pattern signal for determining said operational power information is further recorded to said specific information recording area.
According to the 66th aspect of the invention, in the recording method as set forth in the 56th aspect, said specific information recording area further records an asymmetry information used for determining at least one of a specific first pulse position Tu and a specific last pulse position Td.
According to the 67th aspect of the invention, in a data recording medium having a plurality of concentric or spiral tracks for recording information represented as marks and spaces between the marks, the marks being formed by emitting to a track recording surface an optical beam modulated by a plurality of drive pulses where the drive pulse count is adjusted according to a length of a mark part in the original signal to be recorded to the track, said data recording medium comprises:
a data recording area for recording data, and
a control data zone for prerecording control data as a sequence of embossed marks and spaces,
said control data including at least one of a first pulse position Tu and a last pulse position Td of a drive pulse sequence required by a recording device to record said marks to the data recording medium, and
temporary power information indicative of a power level of an optical beam used for determining a said first pulse position Tu and/or last pulse position Td,
said temporary power information including at least one of the following: a peak power setting, bias power setting, margin constant, and asymmetry.
According to the 68th aspect of the invention, in a data recording medium having a plurality of concentric or spiral tracks for recording information represented as marks and spaces between the marks, the marks being formed by emitting to a track recording surface an optical beam modulated by a plurality of drive pulses where the drive pulse count is adjusted according to a length of a mark part in the original signal to be recorded to the track, said data recording medium comprises:
a data recording area for recording data, and
a control data zone for prerecording control data as a sequence of embossed marks and spaces,
said control data including at least one of a first pulse position Tu and a last pulse position Td of a drive pulse sequence required by a recording device to record said marks to the data recording medium, and
operational power information indicative of a power level of an optical beam used for actual data recording in the data recording area,
said operational power information including at least one of the following: a peak power setting, bias power setting, and margin constant.
According to the 69th aspect of the invention, in a data recording medium having a plurality of concentric or spiral tracks for recording information represented as marks and spaces between the marks, the marks being formed by emitting to a track recording surface an optical beam modulated by a plurality of drive pulses where the drive pulse count is adjusted according to a length of a mark part in the original signal to be recorded to the track, said data recording medium comprises:
a data recording area for recording data, and
a control data zone for prerecording control data as a sequence of embossed marks and spaces,
said control data including at least one of a first pulse position Tu and a last pulse position Td of a drive pulse sequence required by a recording device to record said marks to the data recording medium, and
an asymmetry information used for determining said pulse positions.
Other objects and attainments together with a fuller understanding of the invention will become apparent and appreciated by referring to the following description and claims taken in conjunction with the accompanying drawings.